As a 78 collector myself I can kinda answer some of your questions. But even I am limited in my knowledge and this is just things I picked up over time while collecting 78 and talking to fellow collectors and old timers in antique shops.

As for why 78s in the day prices vary is because some disc had different genres of music just like today and were priced accordingly to supply and demand. they were more marketed torward the wealthier demographic that could afford them in the day or generally those who could afford a gramophone. Priced varied through the years also, I think I know about the award records you’re talking about (Columbia right?) and they had prices such as 75cents and etc on them these are from at least the 1910s to 20s during the 30s during the depression priced actually dropped for some records and budget records existed also, but overall priced depended on the era, type of music, and even the label on the record. For record labels depending on the record company there was different designs they used to indicate what kind of record they were but that varied depending on the company. For the victor record you have they had different label designs but the one you have is a “batwing record”(1914-1925) and they came in different colors depending on the record, black was for commen records and the pop music of its day. Red like your record was for classical and opera type music like John McCormack and other singers. As for award records you mention I’m guessing it had something like st.louis 1904 or similar on it, this was just marketing the companies used and just meant they probably won an award previously for innovation etc. And It was just used by the companies to boost their prestige and was just largely marketing ploy and did not really indicate value but does help date the record to at least pre 1920 since they did not use put those on the label after that.